An axial fan of the kind described above is disclosed in U.S. Pat. No. 4,153,389. In this axial fan, a continuous plastic hub supports the fan blades which are injection molded as one piece with the hub. A metal ring flange is embedded in the plastic hub and the fan is, for example, attached to a fluid-friction coupling with the annular flange and the fluid-friction coupling being driven by an internal combustion engine. The production of such fan wheels is very complex and expensive because a large tool is needed with which the fan is produced in an injection molding operation. The large tool corresponds to the diameter of the fan wheel. The metal annular flange is placed in the injection tool and is injection molded so as to embed the flange in the injected material. For a small number of pieces, the production of such an injection tool is too expensive so that the plastic fan cannot be economically produced in a short run production. For this reason, it is necessary to resort to other measures such as rivet-attached fan blades made of metal.
British patent publication 1,490,055 discloses a fan configuration wherein a metal annular flange is provided witch window-like recesses in which individually manufactured fan blades made of plastic are seated. A plastic hub is then injection molded so as to embed a portion of the fan blades. Three components are connected to each other with this assembly technique, namely, the metal annular flange, the plastic hub and the individual fan blades. A tool for the fan blades as well as a further tool for the plastic hub is required which still means relatively high manufacturing costs. Furthermore, the strength of the connection between the base of the blade and the hub is not adequate for higher loads.